牧草サイレージの揮発性成分のガスクロマトグラフィーによる分析例

Abstract

There is little chemical information concerning the volatile odours of silages. This investigation was carried out to investigate the volatile constituents and the chemical quality of two grass-legume silages which were prepared at different cutting stages and therefore having different chemical composition. The ensiling method was essentially the same as that described earlier1).Approximately 2.5kg of each silage was distilled under normal atmospheric pressure, and 10 liters of distillate from each sample was extracted with proper quantity of ether. The ether extracts were analyzed by gas liquid chromatography employing FID.The results obtained were as follows:1. In the silage A extracts, the n-propyl alcohol and/or n-valeraldehyde and n-capron-aldehyde were the major constituents and ethyl alcohol and n-butyl alcohol, and methyl-n-propyl ketone and butyl acetate and the unknown components of unidentified peak No. 11 were the minor constituents.2. On the other hand, the distillate from silage B contained appreciable amounts of ethyl alcohol and n-propyl alcohol and/or n-valeraldehyde and n butyraldehyde and the unknown constituents of unidentified peak No. 15.3. It was assumed that acetaldehyde and/or propionaldehyde were included in peak No. 1, but they were not separated with ether used for extracting the solvent from the columns employed. Similarly, in peak No. 7 the volatiles were not separated.4. An analytical method for the head space vapor was effective to investigate the constituents of low boiling points.5. The n-butyric and n-caproic acid contents of silage A showed higher values, but in the silage B the contents of acetic and lactic acid were contained in higher values.6. In feeding trials with goats, silage B was more palatable than silage A.